Cosmological Constraints from Sunyaev-Zel'dovich-Selected Clusters with X-ray Observations in the First 178 Square Degrees of the South Pole Telescope Survey

• Main Authors: Benson, B. A., de Haan, T., Dudley, J. P., Reichardt, C. L., Aird, K. A., Andersson, K., Armstrong, R., Bautz, M., Bayliss, M., Bazin, G., Bleem, L. E., Brodwin, M., Carlstrom, J. E., Chang, C. L., Cho, H. M., Clocchiatti, A., Crawford, T. M., Crites, A. T., Desai, S., Dobbs, M. A., Foley, R. J., Forman, W. R., George, E. M., Gladders, M. D., Halverson, N. W., High, F. W., Holder, G. P., Holzapfel, W. L., Hoover, S., Hrubes, J. D., Jones, C., Joy, M., Keisler, R., Knox, L., Lee, A. T., Leitch, E. M., Liu, J., Lueker, M., Luong-Van, D., Mantz, A., Marrone, D. P., McDonald, M., McMahon, J. J., Mehl, J., Meyer, S. S., Mocanu, L., Mohr, J. J., Montroy, T. E., Murray, S. S., Natoli, T., Padin, S., Plagge, T., Pryke, C., Rest, A., Ruel, J., Ruhl, J. E., Saliwanchik, B. R., Saro, A., Schaffer, K. K., Shaw, L., Shirokoff, E., Song, J., Spieler, H. G., Stalder, B., Staniszewski, Z., Stark, A. A., Story, K., Stubbs, C. W., Suhada, R., van Engelen, A., Vanderlinde, K., Vieira, J. D., Vikhlinin, A., Williamson, R., Zahn, O., Zenteno, A.
• Format: Text
• Language: unknown
• Published: arXiv 2011
• Subjects: Cosmology and Nongalactic Astrophysics astro-ph.CO; FOS Physical sciences; Hubble; South Pole; South pole
• Online Access: https://dx.doi.org/10.48550/arxiv.1112.5435; https://arxiv.org/abs/1112.5435

We use measurements from the South Pole Telescope (SPT) Sunyaev Zel'dovich (SZ) cluster survey in combination with X-ray measurements to constrain cosmological parameters. We present a statistical method that fits for the scaling relations of the SZ and X-ray cluster observables with mass while jointly fitting for cosmology. The method is generalizable to multiple cluster observables, and self-consistently accounts for the effects of the cluster selection and uncertainties in cluster mass calibration on the derived cosmological constraints. We apply this method to a data set consisting of an SZ-selected catalog of 18 galaxy clusters at z > 0.3 from the first 178 deg2 of the 2500 deg2 SPT-SZ survey, with 14 clusters having X-ray observations from either Chandra or XMM. Assuming a spatially flat LCDM cosmological model, we find the SPT cluster sample constrain sigma_8 (Omega_m/0.25)^0.30 = 0.785 +- 0.037. In combination with measurements of the CMB power spectrum from the SPT and the seven-year WMAP data, the SPT cluster sample constrain sigma_8 = 0.795 +- 0.016 and Omega_m = 0.255 +- 0.016, a factor of 1.5 improvement on each parameter over the CMB data alone. We consider several extensions beyond the LCDM model by including the following as free parameters: the dark energy equation of state (w), the sum of the neutrino masses (sum mnu), the effective number of relativistic species (Neff), and a primordial non-Gaussianity (fNL). We find that adding the SPT cluster data significantly improves the constraints on w and sum mnu beyond those found when using measurements of the CMB, supernovae, baryon acoustic oscillations, and the Hubble constant. Considering each extension independently, we best constrain w=-0.973 +- 0.063 and the sum of neutrino masses sum mnu < 0.28 eV at 95% confidence, a factor of 1.25 and 1.4 improvement, respectively, over the constraints without clusters. [abbrev.] : 21 pages, 8 figures, submitted to ApJ